It looks like a nice installation except the valve only affects one water tube. You don't think hot water can exchange heat in reverse through the return line, especially once the engine has been shut off? Your A/C will be blowing cold air through a hot heater core. Mounting the valve in the engine compartment would have kept the heat completely out of the cockpit, but you would have had to mount one on each of the two heater hoses. You have a trick way of controlling the water flow, but you have not eliminated the heat for the summer. I hope for your sake the epoxy holds. Yes! They use it to repair engine blocks, sometimes, but when you go to epoxy Plastic, things come apart. I would have installed it differently. You'll Learn. Just my 2 cents, but I have to tell it like it is. "Believe me now, or Believe me later!". Marlin.